Papers by Keyword: Reverse Engineering (RE)

Abstract: In this paper, combining with research situation at home and abroad,the gear parameters extraction methods were compared,including point cloud extraction in reverse engineering, image measurement technology and traditional measurement technique, etc. Analyzes the various technical method,At last,gear parameter extraction of the prospects for development are put forward.

Abstract: Through considering the symmetry constraint characteristics in mechanical product contours, an auto-identification method of two-dimensional symmetrical contour based on feature matching is presented in this paper. Firstly, the feature points are extracted based on contour cloud point data partition and by using offset method, the different distribution rules of axis-symmetrical and rotation-symmetrical images for judging the type of symmetry was studied. The feature description parameters of symmetrical contour were calculated by adopting rotational inertia method and periodic method, which is regarded as the parameters for solving overall constraint optimization of the contour. Examples show that the proposed method can effectively identify the symmetrical contours and their types, and accurately extract the symmetrical constraint features.

Abstract: The fracture surface of con-rod is difficult to be quantitatively described due to its indented macro morphology. Thus, the range of fracture surface defect dimension has no uniform standard. In order to solve this question, 3D software about the digital fracture surface reconstruction was developed by combining the fracture splitting technology of con-rod with reverse engineering, which realized the reproduction of its morphology and completed the real area calculation of the surface. The results show that the fracture surface area processed by fracture splitting is 13.1% larger than that of the plane processed by machining. It represents that the defect dimension range of fracture surface is improved compared to empirical value without reducing the bearing capacity and usability.

Abstract: The conventional precision analysis method of modification and design is qualitative, laborious and time consuming. The precision of reverse parametric modification have direct influences on the quality of the reversed products. In this paper, a quantitative analysis method based on a reverse parametric approach and precision control concept is proposed. Combining with the ATOS scanner system, analyzing every aspect of the precision control and the error distribution, including data acquisition process, reverse reconstruction process and parametric process. In the process of the product reverse parametric modification, general error distribution is mainly composed of data acquisition error, reverse reconstruction error and parametric error. The method of precision control during the reverse parametric modification process is analyzed, according to this method, the total error of parametric modification for die face is 0.089mm, is lower than the accuracy requirement of 0.10mm in the reverse parametric modification process, the reverse modification of the die face of the blade based on precision control is realized. Validity and effectiveness of the method has been confirmed by case studies.

Abstract: Increasing diversity of the products has led to the need of decreasing the design and manufacturing time. Subsequently, an important factor in reducing the design time is to produce parts families from the approached product components. This paper aims to present a method of achieving parts family starting from an iconic model of an existing product, without technical documentation. Firstly the Reverse Engineering (RE) technique is used, because it allows the digitization of the existing product using the 3D scanning equipments. This method supposes dividing the cloud of points, previously obtained, into independent components. Each component identified would be influenced by parameters with default values. This entire stage of parameterization is performed using CATIA software package. Using these components the parts family of the studied product is designed. The aim of the parameterization is to obtain a wide range of components, of various shapes and dimensions, once with the modification of the parameters that define them. Also, in this paper, will be presented a case study to highlight parts family resulted from the parameterized components, for a product belonging to the entertainment industry category.

Abstract: This paper presents how in the Reverse Engineering process can be integrated specific software tools, developed by the authors, which allow for digitized rectangular parts with internal surfaces of revolution, to obtain solid models and CNC program. The first tool named Rotational Axis Primitives and Recognition has implemented a set of algorithms and it is used for recognizing, from a cloud of points associated with a rotational part, the axis and geometrical parameters. The second tool named Hole_Application is created for forward engineering and it can be used to design and manufacture the industrial products with rectangular shape using intelligent technological objects for holes.

Abstract: 3D scanning is one of the basic methods to gather data for reverse engineering. The main drawback of 3D scanning is that its output - the point cloud - can never be used directly to define surfaces or solids useful to reconstruct the electronic 3D model of the scanned part.The paper presents a piece of software designed in VisualLISP for AutoCAD, software that acts as a point cloud to 3D primitives converter. The novelty consists of the method used to find the parameters of the primitive that best fits to the point cloud: the mass properties of regions are used to find the center of a cones cross section. Parts have been scanned and the point clouds processed. The results obtained prove the correctness of the algorithm and of the method applied. A piece of software that processes the point cloud in order to find the 3D primitive that it fits the best has been developed. The output is the 3D primitive that successfully and accurate replaces the point cloud. Some adjacent tools were designed, so the entire software package becomes a useful tool for the reverse engineering user. The ways the researches can be continued and developed are foreseen, as well

Abstract: The study aims to propose an alternative method of segmentation of digitized data. It begins by layering the item's surface. It analyzes the nodes inside a point cloud to detect any consistent shape change. If one detected, then it holds it and looks for the next one which may describe a possible shape change. The points between those two are classified and marked as part of the shape change curvature line. The method remembers the marked points and holds them as central nodes which will later form reference regions. It uses normal vectors behavior methods to detect shape changes along X and Y axis. As any other direction would not be detectable by the bi-dimensional approach it then introduces a morphological parameter capable on its own to fully describe the curvature variation of a given item's surface by means of Gauss's curvature. To evaluate curvature variation, the method proposes that the central node's curvature should be compared with every found limit points. Because of the noise present in any points cloud it establishes a threshold value beyond which points may describe accurately any shape change. This procedure takes place for all analyzed reference regions and collects only those who have a greater value than the threshold one. This considerations may be extrapolated to other types of geometries as well, as it is the case with cylinders or cones.

Abstract: In heterogeneous turbine blades, multiple materials can be synthesized to provide better properties than any single material. In this paper, a new method for turbine blade modeling toward reverse engineering, termed as multi-color distance field, is presented. In this method, the material field describing the material composition continuous or discontinuous variation is associated with the signed distance field describing the geometry model. The method allows the designers to design and optimize no only the geometry but also the material composition of an object. Moreover, both the geometry model and the material information can be easily sliced to manufacture for the object represented using the associated multi-color distance field.

Abstract: A method for tortuous sculptured surface reconstruction of the aeroengine blade was presented. The non-uniform relational B-spline (NURBS) technique method was adopted to reconstruct the surface within a specified accuracy. And it could satisfy our desired requirement in the continuity of the surface, tangent and curvature. The basic theory of NURBS was introduced. And the 3D graphics standard and the graphics library of OpenGL were used to show the result of the tortuous sculptured surface reconstruction on the platform VC++6.0.